Syntax to simplify a series of "If" commands

[Daryl Schrock]

Dear ListServ members:

I have syntax that works, but there should be a more compact/elegant way of
achieving the same result. Does anybody have suggestions on how to simplify
this syntax?

The data is longitudinal data and I am trying to categorize patterns of
change over time in order to get a hands-on feel for how participants'
scores are changing over time. The measure used to assess outcome is a
3-level ordinal scale and in the syntax below is represented by two
variables, BLScore and FnlScore. The syntax creates a new variable,
"Change_BlFnl", that categorizes the pattern of change between participants'
Bl and Final visits.

Here's the syntax that works:

*****Create a pattern variable .

COMPUTE Change_BLFnl = 0.
VARIABLE LABELS Change_BLFnl 'Change Trajectory (categorized)' .

IF  (BLScore = 3 & FnlScore = 3) Change_BLFnl = 1 .
IF  (BLScore = 3 & FnlScore = 2) Change_BLFnl = 2 .
IF  (BLScore = 3 & FnlScore = 1) Change_BLFnl = 3 .
IF  (BLScore = 2 & FnlScore = 3) Change_BLFnl = 4 .
IF  (BLScore = 2 & FnlScore = 2) Change_BLFnl = 5 .
IF  (BLScore = 2 & FnlScore = 1) Change_BLFnl = 6 .
IF  (BLScore = 1 & FnlScore = 3) Change_BLFnl = 7 .
IF  (BLScore = 1 & FnlScore = 2) Change_BLFnl = 8 .
IF  (BLScore = 1 & FnlScore = 1) Change_BLFnl = 9 .

MISSING VALUES Change_BLFnl (0) .
FREQUENCIES VARIABLES=Change_BLFnl .

Thanks!

Daryl

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[Shih, Thomas-2]

It occurs to me that Change_BLFnl = 13 - 3*BLScore - FnlScore.

Thomas

-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of
Daryl Schrock
Sent: Wednesday, April 01, 2009 1:41 PM
To: [hidden email]
Subject: Syntax to simplify a series of "If" commands

Dear ListServ members:

I have syntax that works, but there should be a more compact/elegant way
of achieving the same result. Does anybody have suggestions on how to
simplify this syntax?

The data is longitudinal data and I am trying to categorize patterns of
change over time in order to get a hands-on feel for how participants'
scores are changing over time. The measure used to assess outcome is a
3-level ordinal scale and in the syntax below is represented by two
variables, BLScore and FnlScore. The syntax creates a new variable,
"Change_BlFnl", that categorizes the pattern of change between
participants'
Bl and Final visits.

Here's the syntax that works:

*****Create a pattern variable .

COMPUTE Change_BLFnl = 0.
VARIABLE LABELS Change_BLFnl 'Change Trajectory (categorized)' .

IF  (BLScore = 3 & FnlScore = 3) Change_BLFnl = 1 .
IF  (BLScore = 3 & FnlScore = 2) Change_BLFnl = 2 .
IF  (BLScore = 3 & FnlScore = 1) Change_BLFnl = 3 .
IF  (BLScore = 2 & FnlScore = 3) Change_BLFnl = 4 .
IF  (BLScore = 2 & FnlScore = 2) Change_BLFnl = 5 .
IF  (BLScore = 2 & FnlScore = 1) Change_BLFnl = 6 .
IF  (BLScore = 1 & FnlScore = 3) Change_BLFnl = 7 .
IF  (BLScore = 1 & FnlScore = 2) Change_BLFnl = 8 .
IF  (BLScore = 1 & FnlScore = 1) Change_BLFnl = 9 .

MISSING VALUES Change_BLFnl (0) .
FREQUENCIES VARIABLES=Change_BLFnl .

Thanks!

Daryl

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[Henrik Lolle]

Dear Daryl,

I think that the following should do it (not well tested!), but it
wouldn't be very polite to other folks reading your program.

COMPUTE Change_BLFnl = 0.
VARIABLE LABELS Change_BLFnl 'Change Trajectory (categorized)' .

compute Change_BLFnl=(4-FnlScore)+((3-BLScore)*3).

MISSING VALUES Change_BLFnl (0).
FREQUENCIES VARIABLES=Change_BLFnl.

Best,
Henrik

Quoting Daryl Schrock <[hidden email]>:

> Dear ListServ members:
>
> I have syntax that works, but there should be a more compact/elegant way of
> achieving the same result. Does anybody have suggestions on how to simplify
> this syntax?
>
> The data is longitudinal data and I am trying to categorize patterns of
> change over time in order to get a hands-on feel for how participants'
> scores are changing over time. The measure used to assess outcome is a
> 3-level ordinal scale and in the syntax below is represented by two
> variables, BLScore and FnlScore. The syntax creates a new variable,
> "Change_BlFnl", that categorizes the pattern of change between participants'
> Bl and Final visits.
>
> Here's the syntax that works:
>
> *****Create a pattern variable .
>
> COMPUTE Change_BLFnl = 0.
> VARIABLE LABELS Change_BLFnl 'Change Trajectory (categorized)' .
>
> IF  (BLScore = 3 & FnlScore = 3) Change_BLFnl = 1 .
> IF  (BLScore = 3 & FnlScore = 2) Change_BLFnl = 2 .
> IF  (BLScore = 3 & FnlScore = 1) Change_BLFnl = 3 .
> IF  (BLScore = 2 & FnlScore = 3) Change_BLFnl = 4 .
> IF  (BLScore = 2 & FnlScore = 2) Change_BLFnl = 5 .
> IF  (BLScore = 2 & FnlScore = 1) Change_BLFnl = 6 .
> IF  (BLScore = 1 & FnlScore = 3) Change_BLFnl = 7 .
> IF  (BLScore = 1 & FnlScore = 2) Change_BLFnl = 8 .
> IF  (BLScore = 1 & FnlScore = 1) Change_BLFnl = 9 .
>
> MISSING VALUES Change_BLFnl (0) .
> FREQUENCIES VARIABLES=Change_BLFnl .
>
> Thanks!
>
> Daryl
>
> =====================
> To manage your subscription to SPSSX-L, send a message to
> [hidden email] (not to SPSSX-L), with no body text except the
> command. To leave the list, send the command
> SIGNOFF SPSSX-L
> For a list of commands to manage subscriptions, send the command
> INFO REFCARD
>

************************************************************
Henrik Lolle
Department of Economics, Politics and Public Administration
Aalborg University
Fibigerstraede 1
9200 Aalborg
Phone: [phone]
************************************************************

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